Recently, the scientists at Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences (CAS), Beijing SINOGENE Biotechnology Limited Company and China Agricultural University have generated the world’s first gene knockout cloned dog model by combination of embryo injection of CRISPR/Cas9 with somatic cell nuclear transfer.

The research findings were published in the Journal of Genetics and Genomics.

The dogs are one of the earliest animals domesticated by humans, serving as human companions and are raised to herd livestock, aid hunters, guard homes, perform police and rescue work, and guide the blind for thousands of years. Dogs exhibit close similarities to humans in terms of metabolic, physiological, and anatomical characteristics, suffering from approximately 200 genetic diseases as that in human beings. Thus, dogs are ideal genetic and clinical models to study human diseases. Combination of CRISPR/Cas9 with somatic cell nuclear transfer makes it possible to generate more complex dog models to mimic human disease, which will help provide new animal models for developing new treatment method and drugs for human disease and also accelerate the cultivation of new dog breeds with excellent genetic traits.

The ApoE gene was chosen to generate a cardiovascular disease model for atherosclerosis research. At the initial efforts, a mixture of in vitro transcribed sgRNA and Cas9 mRNA was micro-injected into dog zygotes and two ApoE gene knockout dogs were successfully achieved.

Gene-target puppies, named “Apple” (male) and “Hulu” (female) respectively

(Image from Guangzhou Institutes of Biomedicine and Health, CAS)

To quickly expand the population of gene editing dogs, the scientists then cloned the dogs with somatic nuclear transfer approach. The ear skin fibroblasts of “Apple” were used as donor cells for somatic nuclear transfer to create ApoE gene targeting cloned dogs. A total of 44 cloned embryos were transferred into four surrogates. Among these four recipients, two were pregnant to term and gave birth to three cloned puppies, named as “Longlong”, “Xixi” and “Nuonuo”. The birth of these dogs makes China the world’s second country to independently master the canine somatic cell nuclear transfer technology after South Korea, and the world’s first country to generate a gene knockout cloned dog model. Combining CRISPR/Cas9 with somatic cell nuclear transfer, a large number of animal models with the same genetic background are able to be produced in a short period of time. In present study, in fact, three atherosclerotic dogs with the same genetic mutation as "Apple" were obtained just within six months after its birth.

The related research results were published on Journal of Genetics and Genomics as a cover story in the first issue of 2018. Feng Chong, Wang Xiaomin and Shi Hui contribute to this work equally. Lai Liangxue, Mi Jidong and Zhong Yougang are co-correspondence authors for the article.

For more information, please contact:

Feng Chong: chong-f@sinogene.com.cn

Wang Xiaomin: wang_xiaomin@gibh.ac.cn

Shi Hui: shi_hui@gibh.ac.cn

Zhong Yougang: 18911223116@126.com

Mi Jidong: jidong-m@sinogene.com.cn

Lai Liangxue: lai_liangxue@gibh.ac.cn

Source: Guangzhou Institutes of Biomedicine and Health, CAS